Concrete Volume Calculator — ft, yd, bags
How to use this calculator
Select a shape, enter dimensions in feet, inches, and fractions, then click Add Item to add it to your project list. Add as many items as you need — slabs, columns, walls, footings, tubes, or custom volumes. The running total updates instantly.
Each item appears in the list below with its shape, dimensions, and volume. Delete any item to update the total. Enable the optional Cost Estimate section to price your concrete by ready-mix truck, 80-lb bags, or 60-lb bags.
How to Use the Concrete Volume Calculator
This multi-shape concrete volume calculator helps you plan entire projects. Add slabs, columns, walls, footings, tube fills, or custom volumes to build a complete material list. Enter dimensions in feet, inches, and fractions with ⅛″ precision. Each item’s volume is calculated individually and summed into a project total in cubic yards, cubic feet, or number of pre-mixed bags.
Concrete Volume Formulas
Slab/Rectangle: Length × Width × Thickness
Column (round): π × (D/2)² × Height
Column (square): Side × Side × Height
Wall: Length × Height × Thickness
Footing: Length × Width × Depth
Tube/Hole: π × (D/2)² × Depth
All volumes converted: ft³ ÷ 27 = yd³. Concrete density: 150 lb/ft³ (4,050 lb/yd³).
Bag Coverage
An 80-lb bag of pre-mixed concrete yields approximately 0.6 ft³ (0.022 yd³). A 60-lb bag yields approximately 0.45 ft³ (0.017 yd³). For large pours over 1 yd³, ready-mix delivery is typically more economical and ensures consistent quality.
FAQ
How much waste should I add? Use 5% for simple rectangular pours, 10% for typical projects, and 15–20% for complex shapes or uneven ground.
Can I mix shapes in one project? Yes — add as many items as needed. The calculator sums all volumes automatically.
How accurate is this? Calculations are mathematically exact. Real-world usage may vary due to ground conditions, formwork tolerances, and spillage.
